One episode in season five of How I Met Your Mother, called “Hooked,” revolves around people being kept “on the hook,” romantically speaking, by members of the show’s central gang of friends. “I can’t be with you … right now” is the phrase the pals keep using to string these people along, the “right now” leaving the door cracked open just enough that apparently some poor guy is willing to continue to do Robin’s laundry and rub her feet for the vague possibility of a someday relationship.

This does not make the friends look very good, obviously, but keeping track of and keeping in touch with alternative romantic prospects is a common thing for humans to do, even if it is rarely in such an exaggerated, sitcommy way. A recent study published in Computers in Human Behavior dubs these interactions “backburner relationships." A backburner, as defined by the study, is “a person to whom one is not presently committed, and with whom one maintains some degree of communication, in order to keep or establish the possibility of future romantic and/or sexual involvement.”

The lead study author, Jayson Dibble, an assistant professor of communication at Hope College, told me, “What originally inspired me to think about this is when you meet somebody at a club and trade numbers, you might go through your contacts [later] and say ‘Oh I remember that guy. I might zing him a note and see how he’s doing ... It was inspired by my old days in grad school.”

“When you were meeting everybody at the club?” I asked.

“Well, I say research is me-search,” he replied, laughing.

The communication is key here. A backburner is not just someone who wanders into your thoughts every once in a while—the college sweetheart whose Facebook photos you occasionally browse, or the cute friend-of-a-friend you met on vacation and have always thought you’d really click with, if you lived in the same city. These “what-ifs” only become backburners if you actually reach out to them.

Dibble notes that sometimes backburners know they’re backburners and sometimes they don’t—I suppose it depends on whether the communication in question is more artful than a “hey, what’s up?” text sent at 1 a.m.

There are a couple of competing evolutionary imperatives at play when it comes to keeping people on the backburner. On the one hand, it makes a certain primal sense to explore all the potential mates available, to be sure to get the best deal. But having one long-term partner helps offspring survive, in the rough-and-tumble caveman world often invoked by evolutionary psychology. So commitment provides benefits, in exchange for letting go of other possibilities—the wouldas, the couldas, the shouldas.

According to the investment model of relationships, developed by social psychologist Caryl Rusbult in the 1980s, people who have invested more resources—time, energy, money—into a relationship should be more committed to it, and alternative partners should seem less attractive. One 2007 study found that love motivates people to shut down other options—people who thought and wrote about love for their partners were more able to suppress thoughts about attractive strangers. This is consistent with research that suggests people in relationships don’t pay as much attention to other members of the sex they’re attracted to, and tend to rate others as less attractive.

So, with all this as background, Dibble reasoned that people in committed relationships in his study would keep fewer people on the backburner.

He and Michelle Drouin had 374 undergrads self-report how many backburners they had, whether they talked to them platonically or were more flirty, and what technology they used to keep in touch with these people. Those who were currently in relationships also completed assessments of their investment in and commitment to their relationships, and rated how appealing they thought their alternatives were.

The most frequent ways that people kept up with their backburners were through texts and Facebook. Forty-five percent of participants reported texting backburners, 37 percent reported talking to them on Facebook. Thirteen percent of people still picked up the phone and called the person they were stringing along, and piddling percentages of people kept up with backburners through email, Skype, or Twitter.

What surprised the researchers was that there was no significant difference between the number of backburners kept by people in relationships, and the number kept by single people.

“We were really puzzled by why we didn’t find a relationship between commitment and backburners,” Dibble says. “If the investment model holds, we should have seen a nice strong relationship. Maybe the investment model doesn’t work in the online world.”

In his dissertation at the University of Texas, Austin, Adam Redd West proposed in 2013 that the investment model indeed might not apply when it comes to the Internet. “The online world provides opportunities to evaluate and monitor alternatives … without the need for direct interaction with others,” he writes. The relative privacy of Facebook makes it easier to keep in minimal contact with backburners. Another thing humans tend to do in relationships is attempt to maximize benefits and minimize costs. It doesn’t take much to just comment on someone’s Facebook status, potentially a small cost for the benefit of keeping that person available as a romantic option.

That could also explain why people in relationships still kept in touch with backburners online at nearly the same rates as single people. It seems a little more acceptable to talk to someone on Facebook when you’re not available than it does to meet up with them for dinner or something.

This was a preliminary study—all it really shows is that people keep some of their romantic alternatives on the backburner. That’s not necessarily a new phenomenon: “The behavior of keeping people waiting in the wings, keeping your options open, is nothing new. In the old days it was called keeping people in your little black book,” Dibble says.

This study shows how that behavior plays out today, when people can zing each other notes through a variety of different mediums. The next steps, Dibble says, are to see exactly what people say to keep others on the backburner and examine the ways those conversations play out. He also wants to refine the definition a little more—if you only check in with someone once a year, are they still a backburner? What happens when someone you considered a backburner starts a new relationship, or gets married?

When someone sees their backburner’s Facebook status change, “you’re going to have that ‘ugh’ moment,” Dibble says. “Now your quality of alternatives has shrunk just a bit. If you could develop a backburner relationship over the short term in the lab, and then take it away, man, that would be really cool.”